需求：有这样一个数组
NSArray * srcArr = @[@{@"name":@"张三",@"age":@18,@"sex":@"男"},
@"王五, 18, 男",
@[@"李四", @20, @"男"]];```
取出里面每个item，封装一个Person对象，属性如下：
#import <Foundation/Foundation.h>
@interface Person : NSObject
@property (nonatomic, copy) NSString * name;
@property (nonatomic, assign) NSInteger age;
@property (nonatomic, copy) NSString * sex;
@end
so easy !!!
方法一：
#import <Foundation/Foundation.h>
#import "Person.h"
int main(int argc, const char * argv[]) {
NSArray * srcArr = @[@{@"name":@"张三",@"age":@18,@"sex":@"男"},
@"王五, 18, 男",
@[@"李四", @20, @"男"]];
NSMutableArray * desArr = [NSMutableArray arrayWithCapacity:1];
for (id item in srcArr) {
Person * per = [[Person alloc] init];
if ([item isKindOfClass:[NSDictionary class]]) {
//字典类型
NSDictionary * dict = (NSDictionary *)item;
per.name = [dict objectForKey:@"name"];
per.age = [[dict objectForKey:@"age"] integerValue];
per.sex = [dict objectForKey:@"sex"];
} else if ([item isKindOfClass:[NSString class]]) {
//字符串类型
NSString * str = (NSString *)item;
//以“,”分割
NSArray * coms = [str componentsSeparatedByString:@","];
per.name = coms[0];
per.age = [coms[1] integerValue];
per.sex = coms[2];
} else if ([item isKindOfClass:[NSArray class]]){
//数组类型
NSArray * arr = (NSArray *)item;
per.name = arr[0];
per.age = [arr[1] integerValue];
per.sex = arr[2];
} else {
NSLog(@"暂时没有这种情况");
}
[desArr addObject:per];
}
NSLog(@"desArr = %@", desArr);
return 0;
}
运行结果
desArr = (
"name = \U5f20\U4e09, age = 18, sex = \U7537",
"name = \U738b\U4e94, age = 18, sex = \U7537",
"name = \U674e\U56db, age = 20, sex = \U7537"
)
能完成需求！（这个最重要）
但是，有一天，需求改了！又加了一种不同类型
Person * person = [[Person alloc] init];
person.name = @"Jack";
person.age = 33;
person.sex = @"男";
NSArray * srcArr = @[@{@"name":@"张三",@"age":@18,@"sex":@"男"},
@"王五, 18, 男",
@[@"李四", @20, @"男",
person]];
问题不大，再改改条件语句，加一句else if即可
.....有一天又加了一种不同类型....
.....有一天又加一种不同.....
.....有一天又加.....
........
....
变成这样了，直到你来接手代码了...
if () {
} else if () {
} else if () {
} else if () {
} else if () {
} else if () {
}
.......
else {
}
what the fuck!!!
根本不想看有木有!!!
方法二：
Handler.h
#import <Foundation/Foundation.h>
@class Person;
@interface Handler : NSObject
- (BOOL)canProcess:(id)item;
- (Person *)converToObject:(id)item;
- (void)processWithItem:(id)item
container:(NSMutableArray *)container;
- (void)setNextHandler:(Handler *)nextHandler;
@end
Handler.m
#import "Handler.h"
#import "Person.h"
@interface Handler ()
@property (nonatomic, strong) Handler * nextHandler;
@end
@implementation Handler
- (void)setNextHandler:(Handler *)nextHandler {
_nextHandler = nextHandler;
}
- (BOOL)canProcess:(id)item {
return NO;
}
- (void)processWithItem:(id)item
container:(NSMutableArray *)container {
//能处理当前item
if ([self canProcess:item]) {
Person * person = [self converToObject:item];
[container addObject:person];
} else {
//不能处理，传递给下一个
if (self.nextHandler == nil) {
NSLog(@"没有能够处理的processor了");
} else {
[self.nextHandler processWithItem:item container:container];
}
}
}
//专门用来供子类重写
- (Person *)converToObject:(id)item {
return nil;
}
@end
Handler类是抽象类，只用来继承，每个子类有个nextHandler属性，能够指向下一个责任者（类似单向链表）
- (Person *)converToObject:(id)item
子类重写该方法，来解析item，返回一个Person对象
- (void)processWithItem:(id)item container:(NSMutableArray *)container
如果能处理，就添加到数组中，否则就传递给下一个责任者
- (BOOL)canProcess:(id)item
判断当前责任者能不能处理（解析）该item
ArrayProcessor.h
#import "Handler.h"
@interface ArrayProcessor : Handler
@end
ArrayProcessor.m
#import "ArrayProcessor.h"
#import "Person.h"
@implementation ArrayProcessor
- (BOOL)canProcess:(id)item {
return [item isKindOfClass:[NSArray class]];
}
- (Person *)converToObject:(id)item {
Person * person = [[Person alloc] init];
person.name = item[0];
person.age = [item[1] integerValue];
person.sex = item[2];
return person;
}
@end
重写了父类的两个方法，实现自己不同的地方
StringProcessor.h
#import "Handler.h"
@interface StringProcessor : Handler
@end
StringProcessor.m
#import "StringProcessor.h"
#import "Person.h"
@implementation StringProcessor
- (BOOL)canProcess:(id)item {
return [item isKindOfClass:[NSString class]];
}
- (Person *)converToObject:(id)item {
Person * person = [[Person alloc] init];
//字符串类型
NSString * str = (NSString *)item;
//以“,”分割
NSArray * coms = [str componentsSeparatedByString:@","];
person.name = coms[0];
person.age = [coms[1] integerValue];
person.sex = coms[2];
return person;
}
@end
这里是main
main.m
#import <Foundation/Foundation.h>
#import "Person.h"
#import "ArrayProcessor.h"
#import "ObjectProcessor.h"
#import "StringProcessor.h"
#import "DictionaryProcessor.h"
#import "Handler.h"
int main(int argc, const char * argv[]) {
Person * person = [[Person alloc] init];
person.name = @"Jack";
person.age = 33;
person.sex = @"男";
NSArray * srcArr = @[@{@"name":@"张三",@"age":@18,@"sex":@"男"},
@"王五, 18, 男",
@[@"李四", @20, @"男"],
person];
NSMutableArray * desArr = [NSMutableArray arrayWithCapacity:1];
//初始化各种Processor
ArrayProcessor * arrProcessor = [[ArrayProcessor alloc] init];
ObjectProcessor * objProcessor = [[ObjectProcessor alloc] init];
StringProcessor * strProcessor = [[StringProcessor alloc] init];
DictionaryProcessor * dictProcessor = [[DictionaryProcessor alloc] init];
//连接Processor,把几个处理的对象连接起来
[arrProcessor setNextHandler:objProcessor];
[objProcessor setNextHandler:strProcessor];
[strProcessor setNextHandler:dictProcessor];
//第一个开始处理
for (id item in srcArr) {
[arrProcessor processWithItem:item container:desArr];
}
NSLog(@"desArr = %@", desArr);
return 0;
}
- 创建各种Processor
- 连接起来
- 开始处理
分析
第二种方法：
缺点：
1. 逻辑较第一种复杂
2. 要提前创建所有情况的Processor对象
3. 对于每个对象，都要遍历整个责任链，效率较低
优点：
1. 耦合较低，易于以后扩展
2. 代码可读性高，有益身心健康！
